A range of diseases, medications, trauma and other factors can lead to a person having motion symptoms. Motion symptoms include dyskinesia, in which the person is in a hyperkinetic state, and bradykinesia, in which the person is in a hypokinetic state.
For example, bradykinesia is a key manifestation of Parkinson's disease (PD). L-Dopa, or Levodopa, is often administered to patients having Parkinson's disease, and can have the effect of causing the patient to become dyskinetic for a period of time after administration. However, even for new patients the half-life of levodopa is only of the order about 90 minutes. As Parkinson's disease progresses, the half life of L-Dopa shortens and the effective dose range decreases, making dosage control extremely difficult and complex. This is commonly managed by increasing the dose frequency, sometimes to as many as ten doses each day in an attempt to control symptoms and enable the patient to have a reasonable quality of life. Thus, patients with Parkinson's disease may experience periods of bradykinesia, dyskinesia and normal motor function several times a day and throughout the course of a single dose of L-Dopa.
Even if a satisfactory dosage regime is reached at one point in time, the progressive nature of Parkinson's disease means that neurologists must regularly review a patient's symptoms in order to effectively control the patient's ongoing treatment dosage. Without objective and ongoing monitoring it is very difficult for physicians to avoid prescribing either an excessive dose which overly increases episodes of dyskinesia, or an inadequate dose which does not prevent episodes of bradykinesia. Furthermore conventional clinical treatment relies on a subjective assessment undertaken by a physician, and gives no objective measure to indicate whether a change in dose was effective in improving symptoms.
Further, clinical observation typically only occurs over a short period of patient attendance, usually of the order of tens of minutes, once every 6 or 8 weeks. Fluctuations in kinetic state throughout the day and from one day to the next significantly complicate attempts at assessing the patient's kinetic state. Clinicians often rely on the patient's recollection and/or written diaries to gain an understanding of the ongoing kinetic state of the patient between clinical appointments. However patients can rarely give objective scores, and the effect of a kinetic episode itself can often make it difficult for a patient to make any record whatsoever of the nature of and timing of motor fluctuations.
Monitoring the course of Parkinson's in an individual, and determining when more advanced therapies might become appropriate, requires considerable clinical expertise over an extended period. Advanced therapies for treating symptoms of Parkinson's disease include deep brain stimulation (DBS), Amantadine, Apomorphine by continuous infusion, and levodopa-carbidopa intestinal gel. However, it remains a problem to detect the stage at which conventional therapies such as levodopa are no longer controlling symptoms, and at which more advanced therapies are needed. For some patients, particularly the elderly, the window of time in which to adopt some advanced therapies can be relatively short as DBS can be ineffective if commenced too late, so that failure to promptly recognise the need for advanced therapies can result in the patient entirely missing out on the opportunity to adopt and benefit from such therapies.
In the case of DBS for example, it has been shown that DBS is an effective treatment of PD, for well-selected PD patients. That is, an accurate patient selection is crucial to ensure positive outcomes. Patient selection for DBS usually happens at two stages. First, in clinic, a general neurologist selects the patient as a potential DBS candidate and refers him/her to a DBS surgical centre. Second, at the DBS surgical centre, a team of DBS specialists, including a movement disorders neurologist with expertise in selection and management of DBS patients, determines whether a DBS therapy is recommended for the patient. However, general neurologists who are not expert in movement disorders have difficulty in deciding when to refer patients for consideration for DBS surgery. Indeed studies have shown that the first stage of patient selection suffers from unsatisfactory referral accuracy and that, depending for example on the referring clinician, up to 60% or even 80% of the patients referred are refused by DBS surgical centres. This imposes an unnecessary burden on both the DBS surgical centres, and the patients and their caregivers who undergo unnecessary visits and tests. At the same time, under-referral in the first stage may also exist, which withholds appropriate DBS candidates from the opportunity of being assessed in the second stage and gaining a benefit from DBS therapy.
Moreover, the second stage of DBS patient selection noted above typically involves a comprehensive selection process, including levodopa challenge assessment, brain Magnetic Resonance Imaging (MRI) and evaluation of neuropsychological and psychiatric functions.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.
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